2.11BSD/man/cat2/sigprocmask.0

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SIGPROCMASK(2)	    UNIX Programmer's Manual	   SIGPROCMASK(2)



NAME
     sigprocmask - manipulate current signal mask

SYNOPSIS
     #include <signal.h>

     _i_n_t
     sigprocmask(how, set, oset)
     _i_n_t _h_o_w;
     _s_i_g_s_e_t__t *_s_e_t;
     _s_i_g_s_e_t__t *_o_s_e_t;

     _s_i_g_s_e_t__t
     sigmask(signum)
     _i_n_t _s_i_g_n_u_m;

DESCRIPTION
     The sigprocmask function examines and/or changes the current
     signal mask (those signals that are blocked from delivery).
     Signals are blocked if they are members of the current sig-
     nal mask set.

     If _s_e_t is not null, the action of sigprocmask depends on the
     value of the parameter _h_o_w.  The signal mask is changed as a
     function of the specified _s_e_t and the current mask.  The
     function is specified by _h_o_w using one of the following
     values from <_s_i_g_n_a_l._h>:

     SIG_BLOCK		 The new mask is the union of the current
			 mask and the specified _s_e_t.

     SIG_UNBLOCK	 The new mask is the intersection of the
			 current mask and the complement of the
			 specified _s_e_t.

     SIG_SETMASK	 The current mask is replaced by the
			 specified _s_e_t.

     If _o_s_e_t is not null, it is set to the previous value of the
     signal mask.  When _s_e_t is null, the value of _h_o_w is insigni-
     ficant and the mask remains unset providing a way to examine
     the signal mask without modification.

     The system quietly disallows SIGKILL or SIGSTOP to be
     blocked.

RETURN VALUES
     A 0 value indicated that the call succeeded.  A -1 return
     value indicates an error occurred and _e_r_r_n_o is set to indi-
     cated the reason.





Printed 11/26/99	September 3, 1997			1






SIGPROCMASK(2)	    UNIX Programmer's Manual	   SIGPROCMASK(2)



ERRORS
     The sigprocmask call will fail and the signal mask will be
     unchanged if one of the following occurs:

     EINVAL		 _h_o_w has a value other than those listed
			 here.

     EFAULT		 _s_e_t or _o_s_e_t contain an invalid address.

SEE ALSO
     kill(2), sigaction(2), sigsetops(3), sigsuspend(2)

STANDARDS
     The sigprocmask function call is expected to conform to IEEE
     Std1003.1-1988 (``POSIX'').








































Printed 11/26/99	September 3, 1997			2